A SUPERCELL CALCULATION OF ELECTRONIC STRUCTURE IN SUPERCONDUCTOR Ba 1-x K x BiO 3 (x=0.25, 0.5 and 0.75)

Electronic structure for ordered Ba 1-x Kx)BiO 3 alloys has been calculated with a supercell LMTO method. The results indicate that the band parameters obtained from this approach are more accurate than that from rigid-band approximation. The composition dependence of the band parameters at Fermi surface is given. The hybrid feature of the valence orbitals between the inequivalent oxygen and metal atoms is discussed.